The present invention pertains to the field of image projection systems and in particular to an image projection system for use in a wide range of ambient light conditions.
Due to the ubiquitous nature of advertising, video displays have become an attractive means to convey messages to the public in an interesting and eye-catching manner. Situated in public areas, these display units are typically simple to use and effective at attracting consumer attention. Video display systems currently in use are typically the traditional televisions or box-type projection screens, with these systems typically ranging from a depth of 24 to 120 inches. Many potential buyers consider these types of video display systems to be eyesores and inappropriate for small areas. In addition, these types of video displays may be difficult to install from existing ceiling supports due to their size. Plasma displays may be used for these video displays, however these types of displays are typically very expensive and are only available in limited sizes.
A common approach to create a single large image has been to use xe2x80x9cvideo wallsxe2x80x9d which entail a plurality of screens placed together. Typically, a single video signal is stretched over the plurality of screens in order to create a single image. The difficulty with this type of procedure is that the resolution of a single video feed creating an increasingly larger image results in the loss of quality of the image. In addition, the screens used in this type application are typically enclosed by casings or covers and as such the separation between the adjacent screens creates a plurality of discontinuities or mullions within the image, which reduces the coherency of the image.
Presently, the typical aspect ratios of video display systems are 4:3 or 16:9, and as such in order to produce an image having an aspect ratio outside of the industry norm, the image is typically distorted to form an image having a different aspect ratio. This however does not typically result in a visually pleasing image since the image has been stretched in either the horizontal direction, vertical direction or both.
Canadian Patent Application No. 2,297,981 discloses a projection system in which two or more images are combined to form a composite image. The images are projected side by side onto a screen so that they partially overlap one another. The overlapped portions of the images correspond to one another and the light intensity in this overlap is manipulated or blended to create a seamless transition from one image to the other. The composite image is thus a larger or wider image with higher total resolution. This system overcomes the problem of aspect ratio and the deterioration of image quality due to the increasing of the image size. However, the blending of the overlapping portions of the images results in a system which is expensive due to the required technology for this blending procedure.
An additional problem with projection systems is the dramatic effect which ambient light has on the contrast of the created image. Ambient light conditions tend to xe2x80x9cwash outxe2x80x9d the contrast of the images, resulting in an image which is very poorly defined and difficult to see. Canadian Patent Application 2,128,108 discloses a front projection video display system which achieves high contrast without darkened room conditions by a specific combination and arrangement of polarising filters. This system is effective in rooms where there is normally one light source to control. However it is both expensive and difficult to implement in a large public area where there are normally numerous light sources, for example a shopping centre.
Canadian Patent Application No. 2,079,790 discloses a display that has improved contrast in various lighting conditions. The display which presents the image has enhanced contrast based on its ability to switch between a bright, image-presenting state and a dark, image-less state. This procedure minimises the glare from ambient light reflections, thus enhancing the contrast of the resulting image.
In addition, Canadian Patent Application No. 2,149,552 discloses a display system suitable for high ambient light environments, wherein a lamp is used simply as a light source to illuminate a rear projection display screen. The display screen is a matrix of tiny cells that modulate the light at video rates. Each cell includes a polymer dispersed liquid crystal (PDLC), a focusing lens and a pinhole aperture. When the PDLC is electrically activated, light passing through the PDLC is scattered in many directions and very little light passes through the pinhole aperture limiting what is seen by the viewer. When the PDLC is not electrically activated, light passing through the PDLC is not scattered and the lens of each cell focuses the light through the pinhole aperture hence the viewer sees a bright spot of light.
Each of the above screen designs are capable of reducing the affect of ambient light on the quality of the projected image however, each of these systems require additional components to operate the functionality of the screen itself, in addition to an image creation system, which makes these types of systems expensive.
Therefore there is a need for a projection system which can create images beyond the standard aspect ratio, can be installed in a wide range of ambient light conditions, is inexpensive and is visually appealing.
This background information is provided for the purpose of making known information believed by the applicant to be of possible relevance to the present invention. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present invention.
An object of the present invention is to provide an image projection system and its method of use. In accordance with an aspect of the present invention, there is provided a projection system for the display of images in a wide range of ambient light conditions comprising: a system control means for synchronising two or more images for projection by projection means, wherein said synchronisation of the two or more images provides a means for the generation of a coherent single image; two or more projection means for projecting images, wherein each projection means projects an image onto a unique area of a screen unit, wherein synchronisation of said projection means is controlled by the system control means; and a screen unit comprising one or more screens for receiving the projected images, wherein said one or more screens are compatible with a rear projection system and wherein said one or more screens incorporate a contrast enhancing means which improves the resistance of the projected image to contrast degradation due to a wide range of ambient light conditions, wherein a region separating said projection means and said screen unit is not enclosed.
In accordance with another aspect of the invention, there is provided a projection system for the display of images in a wide range of ambient light conditions comprising: a system control means for synchronising three or more images for projection by projection means, wherein said synchronisation of the images provides a means for the generation of a coherent single image and wherein said system control means stores a plurality of images and sequence information; a screen unit comprising three screens compatible with a rear projection system, wherein said screens have a thickness of less than one inch, wherein said screens are positioned side by side to form the screen unit having a perimeter, wherein the perimeter of the screen unit is enclosed by a frame having a thin profile, wherein each screen receives a projected image from a particular projection means and wherein said screens incorporate a contrast enhancing means which improves the resistance of the projected image to contrast degradation due to a wide range of ambient light conditions; and three projection means for projecting images, wherein said projection means are installed approximately twice the projected width behind the screen unit, wherein each projection means is encased in a protective enclosure and wherein the synchronisation of said projection means is controlled by the system control means, wherein said projection means and said screen unit are suspended from a ceiling and wherein a region separating said projection means and said screen unit is not enclosed.